Arrangement of the Family. • Class, Crustacea ; Sub-Class, Cirript-dia.
Crustacea attached by the anterior end of the head by cement, proceeding from a modified portion of the ovaria : archetype composed of 17 segments, with the first three of large size, and almost always developed into a carapace not wholly exuviated, and capable of various movements ; antennae none ; eyes rudimentary ; mouth prominent, formed by the partial confluence of the labrum, palpi, mandibles, and two pairs of maxillae. Thorax attached to the inter nal sternal surface of the carapace, generally bearing six pairs of captorial, biramous, multi-articulated limbs. Abdomen generally rudimentary. Braochix, when present, attached to the under sides of the carapace. Bisexual ; when unisexual, males parasitic on the female ; male organ single, generally probosciformed, seated at the posterior end of the abdomen. Oviducts none. Metamorphosis complex.
Order I. Thoracica.t Cirripedia having a carapace consisting either of a capitulum on a peduncle, or of an operculated shell with a basis. Body formed of six thoracic segments, generally furnished with six pairs of cirri. Abdo men rudimentary, but often bearing caudal appendages. Mouth with the labrum not capable of independent movements. Larva firstly uniocular, with three pairs of legs ; lastly, binocular, with six pairs of thoracic legs.
Family 1.—Baktnid(e.
Cirripedia without a pedncle; smite and terga furnished with depressor muscles ; other valves united immovably together.
This family was well known to the ancients. The genera seem to have been all confounded under the name of BilAcisor (Balanus) by the Greeks. (Aristotle, ' Hist. Anim.,' book iv. ch. 8, and book v. ch. 15.) Athenmus mentions them more than once ; and (` Deipnoti,' book eh. 11, p. 88) speaks of the large ones with approbation as an article of food. They are the Balani of the Latins ; nor did Lucullus dis dain them. The Chinese eat the soft parts of one of the species (Balanus tintinnabulum), which has the reputation of being like the flesh of the lobster when cooked ; and the delicious qualities of another species, and its high estimation for the table, are referred to in another place. [Bstaxes.]
Sub-Family.—fialan Shell with the rostrum without aim, but having radii ; the lateral compartments all with aim on one side and radii on the other; parictea generally either porose or longitudinally ribbed on their inner surfaces.
Section Scutum and tergum articulated together or overlapping each other : each branchia composed of a single plicated fold.
Genus, Balanus Auctorum. —Compsxtmeuts six ; basis calcareous or membranous ; opereular valves sub-triangular. [Bataxus.] • We are indebted to Mr. Darwin for the following arrangement, the first volume of whose great work on the Cirripedia, including the Lepadidr, pub lished by the Ray Society has alone at present been published.
t The external parts of Cirripedes consist either of a Shell with an Operrulum and the Basis, or of a Capitulum (as called by Mr. Darwin), which is homologous with the shell and operculum, mounted on a Peduncle, which again is homolo gous with the basis. The two valves, to which the animal's body is attached, and which have the power of opening and shutting, are called by Mr. Darwin the Simla ; a second pair of valves, bounding the orifice, at that end at which the cirri are are called the Terpa. At this same end of the shell, or eapitulum, tho medial valve or compartment is called the Carina ; the medial valve or compartment at the opposite end is called the Rostrum: the principal valves or compartments on each side are called the rostra-lateral, lateral, and carino-lateral, or simply the lateral compartments or Latera. In the Palanidie each separate compartment may be said to consist of the wall or parietal portion (generally wedge-formed, with the apex upwards), oad with a Radius (either on one or both sides), or with an Ala (either on one or both sides) the Ala is e quadrangular projection, always overlapped by the adjoining compartment ; the Radius has usually the shape of a wedge, with tho apex downwards; it is exte rior, and overlaps the adjoining compartment.